estimated 30,000 people since march of last year. for more on this potentially explosive situation along the border, we turn to nbc's amon. he's live on the phone from turkey. reset this story for us, if you would, this morning. what happened initially, and where are we now? >> reporter: well, it began on wednesday afternoon when the syrian military essentially fired on this town that was on the syrian side of the border, but according to some, they overshot. one of the mortars landed in the turkish town on the turkish side of the fence. it landed on a house killing a woman, her three children, and an additional woman who was nearby. that sent turkish military into a heightened state of alert. they went into crisis mode. the turkish military fired back artillery rounds into syria, at syrian military positions. according to at least one human rights organization, they killed several syrian soldiers.